We will study the physiologic mechanisms of bile formation including the kinetics of anion excretion, the action of bile-acid choleretics, and the intralobular distribution of labeled bile acids. BIBLIOGRAPHIC REFERENCES: Forker, E.L. Mechanisms of Hepatic Bile Formation. Ann. Rev. Physiol. 39:323-347, 1977. Shen, H., Lonngren, K., Forker, E.L.: Self-similar Solution of a Distributed Model for Transcapillary Exchange and Solute Removal by the Liver. Bull. Math. Biol. In press. 1977.